Not paying for a service I'm not receiving.

I'm writing this on my son's Hallo Peter account. I've been paying for a 10mb uncapped line for months now. Not once. Not even a single second have I received 10mb speed on my line. Still I keep paying the account. Every time I phone Telkom they assure me that the issue has been resolved. It has not. The last time I told them I refuse to pay another sent until my issue is resolved. Guess what. They suspended my account. Phone the billing department. "No sir, this is a technical issue". Phone the Tech department. "We can't do anything until your service has been unsuspended". What the hell. I refuse to pay. Telkom has been steeling my money for months now. I want my account to be credited for the months that I've been paying for a service I've never received. I will only pay for the speeds I'm receiving. And nothing more!!!